SBP GROUP - VOLUNTARY ANNOUNCEMENT - DATA FROM PHASE II CLINICAL TRIAL OF TQC2938 "ST2 MONOCLONAL ANTIBODY" PRESENTED AT EAACI 2026

(Incorporated in the Cayman Islands with limited liability)

Website: www.sbpgroup.com

(Stock code: 1177)

VOLUNTARY ANNOUNCEMENT

DATA FROM PHASE II CLINICAL TRIAL OF

TQC2938 "ST2 MONOCLONAL ANTIBODY" PRESENTED AT EAACI 2026

The board of directors (the "Board") of Sino Biopharmaceutical Limited (the "Company", together with its subsidiaries, the "Group") announces that results from the Phase II clinical trial of TQC2938 "ST2 monoclonal antibody", a national Category 1 innovative drug independently developed by the Group's subsidiary Chia Tai Tianqing Pharmaceutical Group Co., Ltd. ("CTTQ"), in patients with moderate-tosevere seasonal allergic rhinitis (SAR), were presented as an oral presentation at the European Academy of Allergy and Clinical Immunology (EAACI) Annual Congress 2026[1]. TQC2938 is the world's first ST2 monoclonal antibody to report positive clinical data in SAR, offering a potential novel treatment or prevention option for SAR patients with inadequate response to existing therapies.

This study was a randomized, double-blind, placebo-controlled, parallel-group Phase II clinical trial. Enrolled patients were adults with a history of at least 2 years of moderate-to-severe SAR who had shown an inadequate response to intranasal corticosteroid and antihistamine combination therapy. A total of 136 subjects were enrolled and randomized in a 1:1:1:1 ratio to receive a single subcutaneous injection of TQC2938 (210 mg, 420 mg or 630 mg) or placebo. Baseline characteristics were balanced across all groups. The primary endpoint was the mean changes from baseline in daily reflective total nasal symptom score (rTNSS) within 2 weeks of treatment; key secondary endpoints included the mean changes from baseline in daily rTNSS within 4 weeks of treatment, the daily reflective total ocular symptom score (rTOSS) within 2 and 4 weeks of treatment, and the Rhinoconjunctivitis Quality of Life Questionnaire (RQLQ) scores within 2 and 4 weeks of treatment. Safety was also evaluated.

The study results showed that, among the three TQC2938 dose groups, the 420 mg dose group demonstrated the most pronounced overall efficacy in improving nasal symptoms. During the 2-week treatment period, the change in rTNSS score for the 420 mg group compared to the placebo group was -0.97 (95% CI: -2.177 ~ 0.244, p=0.1166); during the 4-week treatment period, the change in rTNSS score for the 420 mg group compared to the placebo group was -1.37 (95% CI: -2.638 ~ -0.103, p=0.0342), indicating a statistically significant and clinically meaningful improvement. Furthermore, compared to the placebo group, the 420 mg group showed statistically significant improvements in all key secondary endpoints, including rTNSS within 4 weeks, rTOSS within 2 and 4 weeks, and RQLQ within 2 and 4 weeks.

Subgroup analyses demonstrated that the 420 mg dose group showed consistent and sustained clinical benefits across all evaluated subgroups. Notably, in the subgroup with baseline eosinophil counts (EOS) <0.3 × 109/L, the 420 mg group (n=24) showed a change in rTNSS score of -1.46 (95% CI: -2.865 ~ –0.057, p=0.0416) compared to the placebo group (n=26) within 2 weeks, indicating a more significant improvement trend.

In terms of safety, the 420 mg dose group demonstrated a favorable profile, with an incidence of treatment-emergent adverse events (TEAEs) related to study drug of 17.65%, which was comparable to that of the placebo group (18.18%). No serious adverse events, Grade ≥3 TEAEs, or deaths were reported in this dose group, and there were no study discontinuations due to TEAEs.

TQC2938 is a humanised IgG2 monoclonal antibody targeting ST2, independently developed by CTTQ. It specifically binds to human ST2 protein, blocking its interaction with IL-33 ligands, thereby simultaneously inhibiting both type 2 and non-type 2 inflammatory pathways. Currently, no biologic agent has been approved for marketing in China for the treatment of SAR patients with EOS <0.3×109/ L. Studies indicate that the prevalence of EOS <0.3×109/L is higher in the general population, accounting for approximately 60%[2], suggesting a substantial unmet clinical need. The positive results from the Phase II study of TQC2938 in SAR patients position it as a promising new treatment option for this group of patient.

Currently, no ST2-targeting biologic agent has been approved for marketing worldwide. TQC2938 is the world's first ST2 monoclonal antibody to achieve a differentiated positioning and report positive clinical results in the treatment of SAR. These Phase II findings provide a solid foundation for advancing into Phase III clinical development.

References:

[1] Y. Zhang, M. Wang, J. Li, et al. Efficacy and Safety of TQC2938 Injection in Patients with Moderate-to-severe Seasonal Allergic Rhinitis: A Multicenter, Randomized, Double-Blind, Placebo-Controlled Phase II Study.OAS-CT1-

Clinical trials on allergic diseases, EAACI Congress 2026.

[2] Zhou Y, Xu Z, Liu Z. Role of IL-33-ST2 pathway in regulating inflammation: current evidence and future perspectives.

J Transl Med. 2023;21(1):902. Published 2023 Dec 11.

By order of the Board

Sino Biopharmaceutical Limited Tse, Theresa Y Y

Chairwoman

Hong Kong, 16 June 2026